Methods of and devices for stabilizing turbine rating, notably in power missiles



March 20, 1962 E. FISCHOFF 3,025,669 METHODS OF AND DEVICES FORSTABILIZING TURBINE RATING, NOTABLY IN POWER MISSILES Filed July 28,1958 5 Sheets-Sheet 1 March 20, 1962 E. FISCHOFF 3,025,669

METHQDS OF AND DEVICES FOR STABILIZING TURBINE RATING, NOTABLY IN POWERMISSILES Filed July 28, 1958 5 Sheets-Sheet 2 W #VVV 9e March 20, 1962E. FISCHOFF METHODS OF AND DEVICES FOR STABILIZING TURBINE RATING,NOTABLY IN POWER MISSILES Filed July 28, 1958 3 Sheets-Sheet 3 PatentedMar. 20, 1952 fire 3,025,669 METHODS OF AND DEVICES FQR STABILIZHQGSTILURBESWE RATING, NOTABLY IN POWER MIS- Etienne Fischoff, 2 RueAnatole France, Vincennes, France Filed July 28, 1958., Ser. No. 751,539Claims priority, application France July 31, 1957 8 Claims. (Cl.6039.27)

This invention relates in general to power missiles and has specificreference to improvements in the methods of and the devices forstabilizing the velocity or rating of turbines, notably in powermissiles.

One of the important problems arising notably in connection with powermissiles using liquid propellants as fuels, especially in the case ofvariable-thrust power missiles incorporating a self-feed turbo-pumpgroup, consists on the one hand in obtaining a perfect stabilization ofthe speed of the pump-driving turbine so as to develop a welldefinedthrust, and on the other hand in ensuring its feed with substantiallyisothermal gases resulting from the combustion of two or three liquidsin the gas generator. This isothermyresulting from an invariability ofthe ratios of the mass flows of the different liquidsis desirable on theone hand in order to protect the turbine against any increase in the gastemperature at certain speeds, and on the other hand for obtaining amaximum operating efficiency of the generator-turbine group.

Many solutions have already been proposed to this problem, but so far asthe applicant is aware none was entirely satisfactory up to now.

It is the essential object of this invention to provide a method wherebythis stabilization as well as this isothermy can be obtained in aparticularly simple, reliable and efiicient manner. This invention isalso concerned with devices for carrying out this method.

Another problem quite as much important is to ensure an adequateoperation of the main combustion chamber or chambers of a power missileof the variable thrust type wherein it is necessary not only toaccurately meter the aggregate output of the two reacting liquids butalso to maintain the ratio of these two outputs to a constant value forobtaining the optimum efficiency values.

It is another object of this invention to provide a particularly simpleand reliable solution of this twofold problem.

The method of this invention consists essentially in applying a strictlyidentical pressure to the different liquids fed to the gas generator ofthe turbine or to the thrust chambers, this pressure being moreparticularly the same as a so-called pilot pressure of fixed or variableor adjustable value; preferably, this pilot pressure is variable eitherunder the operators control or according to a predetermined program.

Thus, all the pressure irregularities or discrepancies arising beforethe device of this invention are somewhat neutralized.

In the following description it is assumed that the invention is appliedto the case of a gas generator in which three liquids are utilized, asmain combustion chambers in which two liquids are present constitute aspecific case of the preceding one.

It will be understood that in this description the termliquid designatessimple liquids proper as well as solutions, liquid mixtures or gases.

The device for carrying out this method comprises essentially as manypressure regulators as there are separate liquids, each regulatorcomprising an inlet and an outlet for the liquid concerned, and an inletfor the pilo pressure, a generator for generating this pilot pressureand possibly a device for varying the value of this pilot pressureeither under the operators control or according to a predeterminedprogram.

According to a first form of embodiment of this invention the pilotpressure utilized is the pressure of one of the liquids concerned asobtaining at the outlet of a conventional-type by-pass valve inserted inthe circuit of the liquid concerned.

A more advantageous form of embodiment of this invention consists ingenerating the pilot pressure in a separate device, this pilo pressurebeing transmitted to the different regulators by a chemically inertliquid, means being provided for varying the value of this pilotpressure.

A regulator according to this invention comprises a flexible diaphragmreceiving the pilot pressure on one face and responsive to the deliverypressure of the liquid on the other face, this diaphragm being connectedto a movable member of which the movements are adapted to modify thecross-sectional area of the passage interconnecting the inlet and outletports for the liquid concerned in the regulator.

Of course, the number of liquids that can be subjected to thisregulation is unrestricted as each liquid flows through its own separateregulator.

Other features and advantages of this invention will appear as thefollowing description proceeds with reference to the accompanyingdrawings forming part of this specifica-tion and illustratingdiagrammatically by way of example a few forms of embodiment of theinvention. In the drawings:

FIGURE 1 is an axial sectional view showing a regulator constructedaccording to the teachings of this invention.

FIGURE 2 is a modified embodiment of this regulator.

FIGURE 3 is a further modification of the regulator of this invention.

FIGURE 4 is a diagrammatic illustration of a first form of embodiment ofan installation according to this invention.

FIGURE 5 is a diagrammatic view illustrating another form of embodimentof this invention.

FIGURE 6 is a diagram illustrating a complete rocket powered aircraftcontrol arrangement according to this invention.

FIGURE 7 is an explanatory diagram, and

FIGURES 8 and 9 are diagrams illustrating two further cases ofapplication of the method and device con stituting the subject matter ofthis invention.

As already pointed out in the above preample, one of the essentialcomponent elements in an installation according to this invention is thepressure regulator, that is, the device which, when subjected to theaction of the pilot pressure as defined hereinabove, limits to thisvalue the liquid pressure obtained in the downstream portion of thecircuit in which this regulator is inserted.

In the form of embodiment illustrated by way of example in FIGURE 1, theregulator comprises a body 1 in which an axial bore 2 is formed; thisbore comprises an inlet 3 for the liquid to be controlled and an outlet4 for the same liquid. These inlet and outlet are off-set along the axisof the body 1 so that a piston 5 slidably mounted in the bore 2 maymodify the cross-sectional area available for the liquid between theinlet 3 and outlet 4, thereby creating a loss of pressure that may beused for modifying the pressure of this liquid at the outlet orifice 4.

The piston 5 is connected by a rod 6 to a diaphragm 7 closing the bore 2beneath the outlet orifice 4; preferably, this diaphragm is flexible,that is, adapted to be deformed without its elasticity or its rigidityinterfering with this movement. The inner face 8 of the diaphragm 7 isresponsive to the outlet pressure of the liquid to be controlled, andits outer face is responsive to the pilot 3 pressure required for aliquid properly introduced through the orifice 10.

The operation of this device in the general case wherein the outputissuing from 4 is not zero, is very simple and appears clearly from thepreceding description.

Three cases may arise: in the first case, the pressure obtained at theoutlet is higher than the pilot pressure; in this case, due to thepressure differential, the diaphragm 7 moves downwards, carries alongthe piston 5 during its movement and thus the piston 5 will throttle thepassage which, in the bore 2, connects the inlet orifice 3 to the outletorifice 4; thus, the liquid pressure at the outlet will be reduced. Inthe second case, the pressure obtained at the outlet is lower than thepilot pressure; under these conditions, the pilot pressure becomespreponderant and moves the diaphragm 7 in the opposite direction,thereby increasing the crossasectional passage available for the liquidto be controlled and therefore the output pressure of this liquid.

Consequently, in the two cases contemplated hereinabove the outputpressure of the liquid to be controlled will tend to become equal to thepilot pressure. When this equality condition is attained, the third casearises wherein the diaphragm is stationary, that is, held in a positionof equilibrium.

Now, this device cannot operate with a sufiicient degree of accuracyunless the piston 5 is free from influences other than those transmittedthrough the diaphragm 7; it is essential, notably, that the piston 5moves without encountering any resistance under the control of thisdiaphragm and consequently that the pressure existing in the chambersituated between the piston and the bottom 11 of the bore be constantlyequal to the output pressure of the liquid to be controlled. Under theseconditions, it is advantageous to pierce through the piston at least onepassage such as 12 to interconnect the two faces of the piston.

In the form of embodiment just described it will be seen that the liquidto be controlled is delivered radially through the orifice 3. As aresult of this specific arrangement, the piston receives a radialdynamic thrust which urges it against the wall of bore 2 with a variableforce, this force generating a frictional resistance also of variablevalue which interferes with the free displacement of the piston. Toavoid this source of errors, the liquid to be controlled may be fed tothe regulators in an axial direction as illustrated in the form ofembodiment of FIGURE 2.

In this example the piston 5 and rod 6 are co-axial with the orifice 3constituting the inlet for the liquid to be controlled. This piston 5 isdisplaceable in a bore 13 of member 14, this member 14 being supportedin the body 1 by arms such as 15, 16. In a third form of embodimentillustrated in FIGURE 3 and to compensate the influence of the dynamicpressure of the fluid fed through the orifice 3 (FIGURE '1), an annularspace 46 may be provided around the piston 5, this annular space 46communicating only through orifices 47 with the piston. 5; theseorifices 47 are disposed symmetrically and pierced through the wall of acylindrical sleeve 48 force-fitted in the body 1. Except for thesemodifications, the device of FIGURE 2 and that of FIGURE 3 are similarto that illustrated in FIGURE 1; more particularly, the operation isexactly the same.

It is an essential object of this invention to provide a pressureregulator of the type described hereinabove in the feed system ofballistic, guided and other missiles, this application beingparticularly advantageous in that it ensures an isothermal fuel feed ofthe gas generators of the turbines of these missiles, as well, on theother hand, as a constant-richness fuel feed of the combustion chambersof rocket engines and of the ram-jets, since the pressure regulatordescribed hereinabove is suitable for regulating gas pressures as wellas liquid pressures.

This specific application constitutes, as already set forth hereinabove,a combination of a device adapted to generate the pilot pressure with asmany regulators of the above-described type as there are fluids of whichthe pressure must be rendered equal to said pilot pressure. A first formof embodiment of this combination is illustrated in FIGURE 4. In thisexample, the liquids delivered to the gas generator of the turbine (notshown) are supplied by pumps 17, I8, 19 and circulate throughdistributors 20, 21, 22 of known type.

In pipes 23, 24, receiving the liquids from pumps 17 and 18respectively, there are inserted regulators 25, 26 for example either ofthe type illustrated in FIGURE 1 or of the type shown in FIGURES 2 or 3.In this case the pilot pressure is that of the liquid supplied by pump19 after this liquid has circulated through the by-pass valve 27 whichmay be adjustable if it is desired to vary the pressure of the gasgenerator.

This form of embodiment of the invention is characterized by manyadvantages, notably that of requiring a number of regulators which isinferior by one unit to the number of liquids utilized, a consequentadvantage being the reduction in the length of piping. Finally, withthis arrangement the drawbacks characterizing the use of separateby-pass valves inserted in each pipe line are definitely avoided.However, this arrangement is attended by certain inconveniences.

More particularly, it is evident that the difierent liquids areresponsive to the law set up by the by-pass valve generating the pilotpressure, which is not an ideal law; as a result, a certain uncertaintystill remains as to the point of stabilization of the turbine, duenotably to the frictional contacts introduced by the guiding of thespring and its valve, as well as by the possible modification of thespring characteristics, due to the frequent presence of corrosiveliquids.

The form of embodiment illustrated in FIGURE 5 is particularlyadvantageous in that it avoids the drawbacks still holding in thepreceding form of embodiment, and that it derives from the invention allthe advantages likely to be obtained therefrom. In this example, aregulator 2, 29, 30 is inserted in each pipe line 31, 32, 33 connectedto the outlet of the feed pumps, respectively. The pilot pressure issupplied by a specific device comprising a bell-shaped member 34containing a liquid 35 fed through ducts 36, 37, 38 to regulators 28,29, 30 respectively. A reserve of air or other gas 39 is provided at thetop of the bell shaped member 34 to permit varia tions in the pilotpressure by displacing the piston 40 obturating this bell-shaped memberwith the assistance of a lever 41; this pressure may be read on the dialof a pressure gauge 42.

This form of embodiment of the invention will therefore permit the totalsuppression of by-pass devices and also of the well-known drawbackscharacterizing these devices. More particularly, the pressures of theliquids are strictly equal irrespective of the rate at which the unit isoperated; on the other hand, with this arrangement the problem of theisothermal feed of gas generators for missile turbines is solvedsatisfactorily.

FIGURE 6 shows diagrammatically another form of embodiment wherein theinvention is applied not only to the feed of a gas generator for thepump-driving turbine but also to the main injectors supplying the mainthrust chamber of the missiles.

In this form of emobdiment the pumps 48, 49 and 50 supply at the sametime the main distributors 51, 52 associated with the main thrustchamber 53 and, through adequate branch lines, the distributors 54, 55and 56 connected to the gas generator 57 of the turbine.

Inserted between the distributors 54, 55 and 56, on the one hand, andthe gas generator 57, on the other hand, are regulators 58, 59 and 60similar to those already described and to which the pilot pressure fromthe device 61 is applied .through ducts 62, 6'3 and 64. This assemblyoperates in the manner already described hereinabove.

Similarly, between the main distributors 51 and 52 on the one hand andthe main chamber 53 on the other hand are inserted regulators 62' and63' to which the pilot pressure of another device 64' is applied throughducts 65, 66. The generator 57 actuates the turbine 67 which drives inturn the three pumps 48, 49 and 50.

These pilot pressures may be adjusted separately by acting independentlyupon the corresponding control levers. If desired, anyone of thesecontrol levers may be interlocked with another lever according to anysuitable servo-action law.

The advantages deriving from this combination are summarized in thediagram of FIGURE 7 in which the curve 68 designates the natural torqueof the turbine, the inclined straight lines such as 69, 70 showing theturbine torques stabilized by the pilot device 61. The line 71 of thisdiagram designates the maximum reaction torque of the pumps and when thepilot device 64' is inoperative or not provided it Will be seen that astabilization is obtainable only on line 71, that is, at the point ofintersection of lines such as 69 and 70, etc. with this line 71.

The introduction of the pilot device 64' and of the relevant regulators62, 63' permits of varying the maximum reaction torque and in this casethis torque is designated by line such as 72, 73, etc. and therefore byvarying the values of the two pilot pressures it becomes possible tostabilize at any point of the plane situated between the curve 71 andthe straight 7 4 designating the maximum permissible speed of theturbine. Consequently, a thrust notably as close as possible to zero maybe obtained in the main chamber 53 while maintaining a pressure in thegenerator which is substantially equal to the minimum pressure ensuringthe proper operation of said generators.

Of course, the forms of embodiment of the invention which are describedhereinabove and illustrated in the accompanying drawings should not beconstrued as limiting the purpose of the invention as they are simpleexamples showing the manner in which the invention may be carried outand to which many modifications may be brought without departing fromthe spirit and scope of the invention as set forth in the appendedclaims.

Thus, notably, an additional loss of pressure may be introduced in eachfluid circuit leading to the generator, this additional pressure dropresulting for example from the provision of needle-valves such as 43, 44and 45 (FIG- URE 5). Similarly, the displacements of piston 40 forvarying the pilot pressure may be efiected automatically according to apredetermined law by substituting a cam of adequate contour, driven by aservo-motor, for the aforesaid lever 41; in this case, a remotecontrolaction may also be provided without difficulty.

Similarly, the pipe lines 36, 37 and 38 (FIGURE 5) may be replaced by asingle line supplying the pilot" pressure to all the regulators such as28, 29, 30, etc.

In FIGURE 8 there is illustrated another form of embodiment of thedevice of this invention in the case of a remote-controlledvariable-output valve. The adjustable pilot pressure is supplied by thedevice 34 of which the piston 40 is connected by a rod 80 to acrank-handle 81, adequate means such as a screw 82 permitting theadjustment of the position of this piston 40 and consequently the valueof the pilot pressure delivered by the device 34 through the pipe line83. The latter leads to a device 84 according to the invention which isconnected on the other hand at 85 to an upstream source of pressure 86and on the other hand at 87 to a downstream source of pressure 88.

In FIGURE 9 another example is shown wherein it is assumed that thereare three sources of pressure 89, 9t] and 91 of which two (90 and 91)are connected through pipe lines 92, 93 to a pair of devices 94, 95according to the invention, the third source (89) being connected on theone hand through pipe lines 96, 97 to the inlets of devices 94, for theliquid at the pilot pressure. The assembly leads into a chamber 98.

From the foregoing it will be readily understood that with thisinvention the pressures of the liquids delivered at 94 and 95 arestrictly equal to each other and also to that delivered at 98.

As already pointed out, many modifications and alterations may bebrought to the various forms of embodiment given herein withoutdeparting from the spirit and scope of the invention as set forth in theappended claims.

What I claim is:

1. In a variable thrust liquid propellant rocket motor for jet propelledvehicles including at least one combustion chamber with exhaust nozzlefor generating said thrust, a gas generator producing burnt gases, threestorage tanks for two combustion-supporting liquids (fuel and oxidizer)to be burnt in said combustion chamber and in said gas generator and fora third coolant liquid to be mixed in said gas generator with said burntgases to limit the temperature thereof to a maximum permissible value,and injectors provided in said combustion chamber and in said gasgenerator to inject said liquids therein, a fluid supply circuit systemcomprising three rotary supply pumps provided each with an inlet and anoutlet and adapted to feed said liquids from said tanks respectively tosaid combustion chamber and to said gas generator, a single gas turbineoperatively coupled to said pumps to drive same simultaneously wherebythe ratios of their speeds remain invariable at all turbine ratings,said gas generator producing said burnt gases to operate said turbine,suction lines connecting said tanks to said inlets of the relevant saidpumps, discharge lines connecting said outlets of said two pumps forsaid combustion-supporting liquids respectively to the relevantinjectors of said combustion chamber and to the relevant injectors ofsaid gas generator and said outlet of said third pump for said coolantliquid to the relevant injectors of said gas generator, cut-off valvemeans inserted in each of said discharge lines, self-actuating pressureregulating devices inserted one in each of said discharge linesdownstream of said cut-off valves and immediately up-stream of saidcombustion chamber and of said gas generator respectively to be eachflown through by the relevant said liquid, said devices being eachsubjected and responsive to an independent constant static referencecontrol pressure so called pilot pressure applied thereto, said devicesbeing adapted to deliver said liquids at strictly constant exitpressures to the relevant injectors of said combustion chamber and tothe relevant injectors of said gas generator whereby said exit pressuresare separately made and kept equal to said pilot pressures respectively,a first control means forming an independent source of stationarypressure fluid of constant inventory to thereby provide a first pilotpressure of determined adjustable value and connected to the tworegulating devices feeding said combustion chamber so that both of themare subjected to a same pilot pressure whereby saidcombustion-supporting liquids are supplied to the relevant injectors ofsaid combustion chamber at strictly constant pressures equal to eachother and to said first pilot pressure, and a second control meansforming an independent source of sta tionary pressure fluid of constantinventory to thereby provide a second pilot pressure of determinedadjustable value, and connected to the three regulating devices feed- 1ng said gas generator so that all three devices are subected to a samepilot pressure whereby said combustionsupporting and coolant liquids aresupplied to the relevant injectors of said gas generator at strictlyconstant pressures equal to each other and to said second pilotpressure.

2. In a variable thrust liquid propellant rocket motor for jet propelledvehicles including at least one combustion chamber with exhaust nozzlefor generating said thrust, a gas generator producing burnt gases, threestorage tanks for two combustion-supporting liquids (fuel and oxidizer)to be burnt in said combustion chamber and in said gas generator and fora third coolant liquid to :be mixed in said gas generator with saidburnt gases to limit the temperature thereof to a maximum permissiblevalue, and injectors provided in said combustion chamber and in said gasgenerator to inject said liquids therein, a fluid supply circuit systemcomprising three rotary supply pumps provided each with an inlet and anoutlet and adapted to feed said liquids from said tanks respectively tosaid combustion chamber and to said gas gen erator, a single gas turbineoperatively coupled to said pumps to drive same simultaneously wherebythe ratios of their speeds remain invariable at all turbine ratings,said gas generator producing said burnt gases to operate said turbine,suction lines connecting said tanks to said inlets of the relevant saidpumps, discharge lines connecting said outlets of said two pumps forsaid combustion-supporting liquids respectively to the relevantinjectors of said combustion chamber and to the relevant injectors ofsaid gas generator and said outlet of said third pump for said coolantliquid to the relevant injectors of said gas generator, cut-off valvemeans inserted in each of said discharge lines, a number of self-actingpressure regulating devices which is one less than the number of saiddischarge lines which all but a selected one discharge line among saidthree discharge lines feeding said gas generator include each one ofsaid regulating devices in sorted therein down-stream of said cut-offvalves and immediately up-stream of said combustion chamber and of saidgas generator respectively to be each flown through by the relevant saidliquids, said regulating devices being subjected and responsive each toan independent constant static reference control pressure so calledpilot pressure applied thereto, said devices being adapted to deliversaid liquids involved at strictly constant exit pressures to therelevant injectors of said combustion chamber and to the relevantinjectors of said gas generator whereby said exit pressures areseparately made and kept equal to said pilot pressures respectively, acontrol means forming an independent source of stationary pressure fluidof con stant inventory to thereby provide a first pilot pressure ofdetermined adjustable value and connected to the two regulating devicesfeeding said combustion chamber to subject both of them to a same pilotpressure whereby said combustion-supporting liquids are supplied to therelevant injectors of said combustion chamber at strictly constantpressures equal to each other and to said first pilot pressure, anadjustable by-pass valve means inserted in said selected one dischargeline down-stream of said cut-off valve involved, and branch linesconnecting said selected one discharge line down-stream of said by-passvalve to each of the two remaining said regulating devices feeding saidgas generator to provide said latter devices with a common second pilotpressure which is the pressure of the liquid in said selected onedischarge line whereby the three said liquids (fuel, oxidizer andcoolant) are fed to the relevant injectors of said gas generator atstrictly constant pressures equal to each other.

3. In a rocket motor, a fluid supply circuit system according to claim1, wherein each of said regulating devices comprises a casing formedwith an inner closed cavity consisting of a substantially cylindricalbore closed at one end and expanding at the opposite end into a shortcoaxial transversely enlarged substantially circular chamber closed by acoaxial bottom of substantially frustoconical shape, a tubular inletorifice and a tubular outlet orifice in said casing adapted fordetachable connection within said discharge line and axially off-setalong and opening in said cylindrical bore in perpendicular relationshipto the axis thereof, whereby a flow passage is provided across saidcylindrical bore from said inlet orifice to said outlet orifice, saidinlet orifice being spaced from said closed end of said bore and saidoutlet orifice being iii) near said opposite end of said bore, a tubularinlet port in said frusto-conical bottom of said casing coaxiallydisposed therewith and with said cylindrical bore and opening through acounter-bore in said circular chamber, said inlet port being adapted fordetachable connection with said control means to receive therethroughsaid pilot pressure, an inner annular recess in said casing coaxiallysurrounding said cylindrical bore and communicating therewith and withsaid inlet orifice, a movable piston slidably mounted with a determinedlateral clearance in said cylindrical bore and having a front end facefacing said closed end of said bore and an opposite rear end face facingsaid opposite end of said bore, said piston being formed with at leastone passage opening on either of its opposite faces and extendingparallel to its axis whereby said piston is substantially entirelysurrounded by said liquid flowing through said bore and is adapted tomodify by its displacement the cross-sectional area of said flow passagehence the pressure loss therethrough, a substantially soft yieldingnonresiliently deformable diaphragm means in said casing tightlycoaxially mounted in said circular chamber to form a transversepartition halving said chamber thus separating said bottom from saidcylindrical bore and responsive on the one side to the exit pressure ofsaid liquid and on. the other side to said pilot pressure, whereby anydifference between said pressures causes a deflection of said diaphragmwhich moves unconstrainedly within said chamber, an integral stemdirectly and rigidly connecting said diaphragm to said rear end face ofsaid piston whereby the latter is caused to move according to the actualdeflection of said diaphragm, and a stop means provided on that side ofsaid diaphragm which faces said bottom, said stop means registering withsaid counter-bore which is adapted to accommodate said stop means tolimit the deflection of said diaphragm when said pilot pressure isreleased whereby said diaphragm is allowed to be backed by and toconform to said bottom to prevent undue stresses therein.

4. In a rocket motor, a fluid supply circuit system according to claim2, wherein each of said regulating devices comprises a casing formedwith an inner closed cavity consisting of a substantially cylindricalbore closed at one end and expanding at the opposite end into a shortcoaxial transversely enlarged substantially circular chamber closed by acoaxial bottom of substantially frustoconical shape, a tubular inletorifice and a tubular outlet orifice in said casing adapted fordetachable connection within said discharge line and axially off-setalong and opening in said cylindrical bore in perpendicular relationshipto the axis thereof, whereby a flow passage is provided across saidcylindrical bore from said inlet orifice to said outlet orifice, saidinlet orifice being spaced from said closed end of said bore and saidoutlet orifice being near said opposite end of said bore, a tubularinlet port in said frusto-conical bottom of said casing coaxiallydisposed therewith and with said cylindrical bore and opening through acounter-bore in said circular chamber, said inlet port being adapted fordetachable connection with said selected one discharge line to receivetherethrough said pilot pressure, an inner annular recess in said casingcoaxially surrounding said cylindrical bore and communicating therewithand with said inlet orifice, a movable piston slidably mounted with adetermined lateral clearance in said cylindrical bore and having a frontend face facing said closed end of said bore and an opposite rear endface facing said opposite end of said bore, said piston being formedwith at least one passage opening on either of its opposite faces andextending parallel to its axis whereby said piston is substantiallyentirely surrounded by said liquid flowing through said bore and isadapted to modify by its displacement the cross-sectional area of saidflow passage hence the pressure loss therethrough, a substantially softyielding nonresiliently deformable diaphragm means in said casingtightly coaxially mounted in said circular chamber to form a transversepartition halving said chamber thus separating said bottom from saidcylindrical bore and responsive on the one side to the exit pressure ofsaid liquid and on the other side to said pilot pressure, whereby anydifierence between said pressures causes a deflection of said diaphragmwhich moves unconstrainedly within said chamber, an integral stemdirectly and rigidly connecting said diaphragm to said rear end face ofsaid piston whereby the latter is caused to move according to the actualdeflection of said diaphragm, and a stop means provided on that side ofsaid diaphragm which faces said bottom, said stop means registering withsaid counter-bore which is adapted to accommodate said step means tolimit the deflection of said diaphragm when said pilot pressure isreleased whereby said diaphragm is allowed to be backed by and toconform to said bottom to prevent undue stresses therein.

5. In a rocket motor, a fluid supply circuit system according to claim3, wherein each of said control means comprises a contained gas forgenerating said pilot pressure, a contained chemically inert liquid incontact with said gas, ducts connecting said control means with saidinlet ports of said regulating devices respectively associatedtherewith, said inert liquid filling said ducts and the relevant halvesof said circular chambers in said regulating devices for transmittingthereby said pilot pressure from said gas to said diaphragms and meansfor varying the value of said pilot pressure according to requirements.

6. In a rocket motor, a fluid supply circuit system according to claim4, wherein said control means comprises a contained gas for generatingsaid pilot pressure, a contained chemically inert liquid in contact withsaid gas, ducts connecting said control means with said inlet ports ofsaid regulating devices respectively associated therewith, said inertliquid filling said ducts and the relevant halves of said circularchambers in said regulating devices for transmitting thereby said pilotpressure from said gas to said diaphragrns and means for varying thevalue of said pilot pressure according to requirements.

7. In a rocket motor, a fluid supply circuit system according to claim3, wherein adjustable restriction means are provided in each of saiddischarge lines down-stream of each of said regulating devices to permitof locally modifying the cross-section of the flow passage hence thepressure drop in said discharge lines between said regulating devicesand said injectors to compensate for casual pressure drop decreases dueto wear of said injectors and for casual pressure drop increases due toobstruction of said injectors in order to restore the actual pressurelosses to their initial values and means being provided to operate saidrestriction means according to requirements. 7

8. In a rocket motor, a fluid supply circuit system according to claim4, wherein adjustable restriction means are provided in each of saiddischarge lines including said regulating devices and down-streamthereof to permit of locally modifying the cross-section of the flowpassage hence the pressure drop in said discharge lines between saidregulating devices and said injectors to compensate for casual pressuredrop decreases due to wear of said injectors and for casual pressuredrop increases due to obstruction of said injectors in order to restorethe actual pressure losses to their initial values and means beingprovided to operate said restriction means according to requirements.

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